The present invention relates to model aircraft and has particular reference to ducted fan jet propulsion means thereof. There has been a lack of readily available ducted fan units for model aircraft, although piston engines for propeller driven craft are in abundance. The present invention fills this void by providing a device which is driven by the commonly available model aircraft engine yet acts like a fan propulsion unit. The ducted fan engine is specifically designed for easy kit fabrication by the producer and simple construction by the modeler.